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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: Laboratory Activated sludge plant receiving sewage from the Wupper area water authority
- Storage conditions: aerobic conditions in the dark at 20 ± 1 ºC
- Preparation of inoculum for exposure: The test substance was suspended in a mineral medium, inoculated with activated sludge and incubated for 28 days
- Concentration of sludge: 0.03 g ss/L
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
The test substance was suspended in a mineral medium, inoculated with activated sludge and incubated for 28 days under aerobic conditions in the dark at 20 ± 1 ºC. The biodegradability of the test substance was determined during this period with a respirometer which registered the oxygen consumption.
Analytical Parameter: Oxygen consumption
Sampling: Every 2 days
Controls: Inoculum blank & reference compound and inoculum
Statistics: No statistical methods were employed
Reference substance:
aniline
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Details on results:
Kinetic of test substance (in %):
= 0 after 28 day(s)
Kinetic of control substance (in %):
ca. 80 after 14 day(s)
Degradation products: not measured
Results with reference substance:
The biological degradability of the reference compound aniline was ca 80% after 14 days
Interpretation of results:
under test conditions no biodegradation observed
Executive summary:

A GLP Guideline study (OECD 301) is available for this test substance. The biological degradation of Diuron at the end of the 28 day test was 0% based on BOD indicating that Diuron is not readily biodegradable under aerobic conditions.

Description of key information

Diuron is not readily biodegradable according to the criteria of the test.

Key value for chemical safety assessment

Additional information

The biological degradation of Diuron at the end of the 28 day test was 0% based on BOD, therefore no biodegradation of Diuron was observed under aerobic conditions (Müller, 1991).